[ee122] HW 2 - Question 3 General question

The prompt says that latency is 12ms. If I remember correctly, latency
is the delay in a network for 1 packet to get from point A to point B.
Now, if the bandwidth is 12Mbps, wouldn't the latency (per packet) be:
( 1500bytes * 8bits/byte ) / ( 12*10^6 bits / sec ) = 1ms
My confusion arose because I see that a latency is given, but there are
two different packet sizes. The regular one and the ACK. So I figure the
smaller one should be faster.. maybe I'm missing something?
Thanks in advance.
Anthony